a=['zero', 'one', 'two', 'three', 'four', 'five', 'six',
'seven', 'eight', 'nine']
lst=[]
b=input ()
b=b.split(' ')
s=''
q1=0
k=0
q2=0
for p in range (2, 1500):
    pr = True
    for i in range(2, int(p ** 0.5 + 1)):
        if p % i == 0:
            pr = False
            break
    if pr:
        lst.append(str(p))
for i in b:
    if i in a and len(b)==3:
        s=s+str(a.index(i))
        k=1
    else:
        print ('Wrong input')
        break
if s in lst :
    print (s)
elif k==1:
    for i in range (11):
        if str(int(s)+i) in lst:
            ql=int(s)+i
            break
    for i in range (1,-11,-1):
        if str(int(s)+i) in lst:
            q2=int(s)+i
            break
    if abs(abs(q1)-int(s))<abs(abs(q2)-int(s)):
        print (q1)
    else:
        print (q2)

